Green Energy
Energy efficiency and electrical installations
Jake Green, Scolmore’s technical engagement manager, provides insight into the integration of electricity generation, energy efficiency management systems and energy storage into a prosuming whole.
T
he ever-rising cost of energy has become a significant factor in the drive to improve energy efficiency. Whilst data gathered by the Government in England and Wales highlights that since 2005 there has been a downward trend in the usage of gas and electricity in all properties irrespective of their age, present price trends are on a rapid upward curve. The current prosuming technologies (PV, generators etc.) provide an opportunity to integrate both electricity generation, energy efficiency management systems and energy storage into a prosuming whole, enabling a more varied means of supplying and using electricity. The introduction of Chapter 82 into Amendment 2 of BS 7671 has provided additional guidance for the integration of energy efficiency/ energy management into the operation of electrical installations.
This article briefly considers some of the guidance provided by the Appendix 17 (Energy Efficiency) detailed in BS 7671 and the Harmonised Document published by BSI, Low- voltage electrical installations Part 8-1: Functional aspects – Energy efficiency (IEC 60364-8-1: 2019) and discusses some of the factors to consider when looking at energy efficiency and energy management.
Legislation
In all parts of the UK there are specific requirements detailed in the associated building regulations for energy efficiency. In England, reference should be made to Part L and the associated guidance found in Approved Documents L1 and L2; in Scotland reference should be made to the Building Regulations Technical Handbooks (Domestic and non- domestic).
Appendix 17
The purpose of Appendix 17 is to ‘…provide additional recommendations for the design and erection of electrical installations, including installations having local production and storage
28 | electrical wholesaler February 2024
of energy, for optimising the overall efficient use of electricity.’ Whether human behaviour has a greater impact on energy usage than any energy management system, controls will play a significant role in any design considerations (clause 17.2).
It is the case that little thought is given for ‘… optimising the overall efficient use of electricity’ when an electrical installation is being designed. For example, cable sizes are determined based upon the design current of the circuits, the rating of the protective device(s), and various rating factors. The selected cable is designed to limit the rise in temperature during current-carrying conditions to a safe level within the limitations of the cable. Currently there is no regulatory imperative for the designer to take account of any energy efficiency factors.
“In all parts of the UK there are specific requirements detailed in the associated building regulations for energy efficiency.”
Clause 17.11 (Appendix 17) suggests that the design of an electrical installation should consider energy efficiency at every stage, including the impact of different load demands, usage etc. One implication of this is that distribution boards will need to enable the segregation of circuits supplying each zone or mesh as defined. It will be necessary for the user to be able
to monitor the electrical installation (clause 17.12) and, therefore, the measurement of total consumption in kWh for every hour of each day should be logged and stored for a minimum of one year and be accessible to the user. However, a simplistic approach to energy efficiency might fail to consider, for example, embodied energy – that is the ‘unconsidered’ energy demands in the production of more/ larger boards/cables and the like. The designer should not, therefore, simply increase cable sizes to limit voltage drop, or create meshes and zones thinking that these alone will necessarily reduce energy usage.
Design considerations
When considering the availability of electrical energy, the designer and user will have to consider, as a minimum, the following (clause 17.2):
Selection of energy efficient appliances Assignment of load priority for use as an input of the load optimisation process – including any load shedding
The intended use of the installation in providing an energy efficient design, and The provision of a manual override facility enabling the user to take control from any automatic functions.
The design requirements detailed in clause 17.3 are: • •
Load energy profile
Availability of local generation, such as PV, wind, generator and the like
ewnews.co.uk
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44
